Children with cancer undergoing intensive chemotherapy (CT) regimens experience many side effects among which oral mucositis (OM) is one of the most debilitating. Modifications of CT's schedule and prolonged hospitalization may be necessary in presence of OM, causing poor general conditions and debilitation. Moreover, the use of narcotic analgesics and total parenteral nutrition may be required, triggering not only a physical deficit but also an economic burden. Despite the frequency and impact of OM among children with cancer, there is no consensus on standard therapy for this condition. Previous studies demonstrated that high power laser therapy can help the maintenance of nutritional status in patients with OM and can remarkably reduce costs/resources needed. Laser therapy has evidence of efficacy in reducing symptoms and in preventing the onset of OM in adult cancer patients but only one randomized controlled trial, with a limited number of children enrolled, supports its use in children for treatment of OM induced by chemotherapy.